Formed vane elements for liquid-vapor separators

ABSTRACT

Apparatus for separating entrained liquids from a traveling stream of gas or vapor wherein the gas travels through sinuous paths formed by generally vertical vanes of zig-zag crosssectional configuration arranged in side-by-side relationship and provided with vertically extending channels which collect water droplets impinged upon the surfaces of the vanes as the gas travels therethrough. The invention is characterized in that each vane, including the collecting channel therefor, is fabricated from a single sheet of metal formed as by stamping, bending or roll forming into the desired cross-sectional configuration. This reduces the cost of the product and eliminates tolerance problems encountered when an attempt is made to obtain the desired crosssectional configuration by welding.

Sokolowski 11] 3,805,496 Apr. 23, 1974 FORMED VANE ELEMENTS FOR LIQUID-VAPOR SEPARATORS [75] Inventor: Peter F. Sokolowski, Media, Pa.

[7 3] Assignee: Westinghouse Electric Corporation,

Pittsburgh, Pa.

[22] Filed: Feb. 2, 1970 21 Appl. N04 7,694

52 us. c1. .Q 55/440 [51] Int. Cl B0ld 45/08 [58] Field of Search 55/183-188, 55/440 [56] References Cited V UNITED STATESPATENTS 1,896,656 2/1933 Anderson 55/440 2,007,966 7/1935 Fletcher 122/491 2,643,736 6/1953 Smith 55/440 3,520,116 7/1970 Good .1 55/440 3,527,030 9/1970 Hungate 55/440 FOREIGN PATENTS OR APPLICATIONS 223,099 6/1910 Germany 55/440 Primary Examiner-Bernard Nozick Attorney, Agent, or Firm-Z. L. Dermer [57] ABSTRACT Apparatus for separating entrained liquids from a traveling stream of gas or vapor wherein the gas travels through sinuous paths formed by generally vertical va ne s of gig-zag cross-sectional configuration arranged in side-by-side relationship and provided with vertically extending channels which collect water droplets impinged upon the surfaces of the vanes as the gas travels therethrough. The invention is characterized in that each vane, including the collecting channel therefor, is fabricated from a single sheet of metal formed as by stamping, bending or roll forming into the desired cross-sectional configuration. This reduces the cost of the product and eliminates tolerance problems encountered when an attempt is made to obtain the desired cross-sectional configuration by welding.

8 Claims, 5 Drawing Figures PATENTEI] APR 23 19v.

SHEET 2 OF 2 FIG. 5.

FORMED VANE ELEMENTS FOR LIQUID-VAPOR SEPARATORS sary to dewater steam from a boiler before it is fed into where the water content is removed from the steam before it passes into the turbine. Such vane separators also find utility in any application where it is necessary to separate entrained liquid droplets from a gas as, for example, in chemical and natural gas applications.

The vane-type separator consists essentiallyof a housing having an inlet and outlet section for the gas and a plurality of vertically extending vanes arranged in side-by-side relationship which define, in crosssection, a zig-zag configuration. With this arrangement,

, the gas must pass through sinuous passages formed by the spaced vanes in traveling from theinlet to the outlet. In so doing, it is subjected to multiple changes in direction as it travels through the sinuous paths. This causes a turbulent condition of the gas which impinges against the sides of the vanes, causing any entrained droplets of liquid to adhere to the surfaces of the vanes. At the trailing edge of each flat surface of a vane forming a, zig-zag configuration is a vertical channel which collects the liquid droplets and directs them downwardly into a collecting basin from where the water, in the case of a steam turbine, is returned to the boiler.

In the past, thevanes used in a separator of this type have been fabricated from formed sections of generally zig-zag configuration having strips spot-welded thereto to form the aforesaid collecting channels. Because of I the difficulties encountered in positioning and holding the strips during spot-welding, the resulting pockets which serve as water catchers are not uniform in size. Large pocket gap variations will result in differences in moisture carry-over performance, meaning that in the caseof turbine applications one steam generator'rnay not perform as well. as another because of differences in pocket dimensions. Pocket gap variation may also result in steam generator performance being different from tests conducted in the laboratory. Furthermore, extensive positioning equipment for holding the strips during spot-welding together with a large amount of labor make prior art vanes formed from a plurality of parts inherently expensive.

SUMMARY OF THE INVENTION Briefly, the invention eliminates the difficulties encountered in attempting to weld channels to a vane for a separator by forming the entire vane, including the which, at its end opposite the channel, is connected by a bend to the next portion of the vane which has a channel formed therein in the same manner. All channels'face in the same direction and are located at the trailing ends of the flat surfaces of the vanes (i.e., the trailing ends as viewed from the direction of gas flow through the separator), whereby water collected on the flat surfaces of the vanes will travel backwardly to the channels and be directed downwardly into a collecting ba'sin.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a cross-sectional view of the top portion of a nuclear steam generator provided with moisture separators formed in accordance with the invention;

FIG. 2 is a cross-sectional view of the separators of the invention taken substantially along line II-II of FIG. 1;

FIG. 3 is an enlarged top view of a complete vane assembly for one of the four banks shown in FIG. I, incorporating a housing for holding the vanes in place;

FIG. 4 is a cross-sectional view taken substantially along line IVIV of FIG. 3 showing the jacking plate of the vane assembly; and

FIG. 5 is a top view of a plurality of spaced vanes fabricated in accordance with the teachings of the invention and showing the manner in which the moistureladen gas passes therethrough.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference now to the drawings, and particularly to FIG. 1, the upper portion of .a nuclear steam generator 5 is shown and includes an outer housing 10. Steam generated therein, in a manner not shown but well known in the art, passes upwardly along the direction of the arrows through a passage 12 containing acentrifugal separator 14. From separator 14,, the steam passes into a chamber 16 of generally annular configuration surrounding a four-bank moisture separator, generally indicated by the reference numeral 18. As shown in FIG. 2, the moisture separator 18 includes four banks 20A, 20B, 20C and 20D of vanes 22, the details of which will hereinafter be described. The steam, after passing from chamber 16 through the vanes 22 in banks 20A-20D passes into a generally rectangular space 24 within the banks and thence upwardly through a perforated plate 26 to a steam outlet 28.

In passing through the vanes 22 of the banks 20A- 20D, moisture is removed from the steam in a manner hereinafter described such that when the gas reaches the outlet 28, it is essentially free from moisture. The vanes 22 are supported on perforated plates 30 at the bottom of each bank 20A-20D. The moisture collected by the vanes 22 is directed downwardly through the perforated plates 30 into a chamber 32 and thence into a basin 34 where it flows into a drain 36 leading back to the lower or steam generating portion of the steam generator 5, not shown. Alternatively, the condensate can be drained directly back to the lower portion of the steam generator 5 from the chamber 32 by means of a conduit 38. Additional drains 40 and 42 are provided for draining any moisture which collects within the space 24 within the banks 20A-20D and above the banks, respectively. Walls 40A and 408 separate the moisture-laden chamber 16 from the chamber 24 within the four-bank moisture separator 18 and the chamber 42 above the separator which communicates with the outlet 28. If desired or necessary, a perforated plate 44 may be positioned immediately in front of the vanes 22 of the separator 18 such that the moistureladen gas, in striking the perforated plate, will have its moisture particle size reduced before it passes through the vanes 22. The perforated plate 44 also increases the pressure drop, thereby producing a more uniform distribution of flow across the face of the separator. The second perforation plate 26 can be added at the outlet section to help produce a more uniform distribution of flow across the face of the separator. Perforated plate 44 can be used either in addition to plate 26 or by itself.

A typical top cross-sectional view of a separator bank is shown in FIG. 3. It includes a housing 46 having channel-shaped end plates 48 and 50 interconnected by top and bottom stringers 51 and 52 (FIG. 1), only the bottom stringers 52 being shown in FIG. 3. This leaves large openings 54 in the side walls of the bank assembly such that the gas or vapor may flow through the bank from one opening to the other in the direction of arrow 55. The assembly of vanes 22 is bounded on one side by a jacking plate 56 and on the opposite end by the end plate 48.

Spacers 58 are welded to the vane 22A which in turn is welded to the jacking plate 56. Consequently, the vane 22A, the jacking plate 56 and the spacers 58 can be removed from the housing 46 as a single unit (FIG. 4). Spacers 60 and 62 are welded to vane 223 but not to the next successive vane 22C (not shown in FIG. 3) such that vane 22B and its spacers 60, 62 can be removed as a unit. The same is true of all other vanes except the last vane 22N which, in addition to spacers 60 and 62 has welded to it spacers 64 which serve as stops and limit the distortion suffered by vane'22N as the assembly is jacked together by means of threaded screws 66. The entire assembly is supported on the perforated plate 30 shown in FIG. 1; and when all vanes are in place, they are held snugly between the jacking plate 56 and end plate 48 of the housing 46. An elevational view of the jacking plate 56 is shown in FIG. 4.

A top view of the vanes 22 is illustrated in FIG. 5. In accordance with the invention, each vane is fabricated from a single sheet of metal which is formed by a press brake, by stamping or by forming rolls into the configuration shown. It will be noted that each of the vanes 22A through 22D comprises a plurality of adjoining portions 68A, 68B, 68C, and so on, disposed at an angle with respect to each other to form a generally zigzag configuration. Each portion, such as portion 68B, comprises a first section 70 connected at an angle, as by bend 72 to the next portion 68C and folded upon itself to form a lip 74 which extends along the entire vertical length of the vane. Contiguous with the folded section 74 is a U-shaped channel 76 also extending along the length of the vane and having one side comprising the folded section 74. Finally, the U-shaped channel section is contiguous with a straight section 78 parallel to the lip 74. The section 78 is connected at an angle, as by bend 80, to the section 70 of the next preceding portion 68A of the vane.

A gas stream laden with liquid particles entering the vanes from the right as viewed in FIG. will travel along the direction of the arrows shown; and in so doing it will follow a sinuous path, its direction of movement being constantly changed as it flows through the paths defined by the vanes. This causes a turbulence in the gas; and the entrained droplets are forced against the walls of the vanes where they impinge and adhere to the vanes surface. This liquid then moves to the channels 32 and then drains downwardly into the basin 18 shown in FIG. 1. It will be noted that as the gas travels from right to left in FIG. 5, the entrained liquid droplets decrease in number until, when the gas reaches the left ends of the vanes, it is essentially free from moisture.

With the vanes of the present invention, much closer tolerances in the dimension D, FIG. 5, (Le, the width of the channel) can be achieved than is possible with the spot-welded strips used in the prior art and described above. Weldedvanes having a desired dimension D of 0.150 inch, for example, have a variation in this dimension from about 0.180 inch to 0.120 inch or a tolerance variation from desired of about i 20 percent. With the vanes shown herein, on the other hand, the actual dimension D for a desired 0.130 inch will be in the range of about 0.150 to 0.110 inch and can be held to 0.140 to 0.120 inch for a tolerance variation from desired of only about i- 8 percent. Maintenance of close tolerances is highly important because the width of the channel sections, D, affects the desired operating characteristics and capacity of the separator.

The present invention thus provides a vane for a separator formed from a single sheet of metal rather than a corrugated sheet having L-shaped members welded thereto to form pockets. This eliminates the problems encountered in welding and materially reduces the cost of the product. Although the invention has been shown in connection with a certain specific embodiment, it will be readily apparent to those skilled in the art that various changes in form andarrangement of parts may be made to suit requirements without departing from the spirit and scope of the invention.

I claim as my invention:

1. In apparatus for separating entrained liquids from a traveling stream of gas wherein the gas travels through sinuous paths formed by generally vertical vanes of zig-zag cross-sectional configuration and provided with vertically extending channels which collect liquid droplets impinged upon the surfaces of the vanes as the gas travels therethrough under turbulent conditions; the improvement in said vanes characterized in that each vane is formed from a single sheet of metal, the vane having adjoining portions disposed at an angle with respect to each other to form said zig-zag configuration, each of said portions having a first section connected at an angle to the preceding portion and folded upon itself to form a folded section and a lip extending along the length of said vane,- a reversely bent section contiguous with said folded section and forming a U- shaped channel spaced from the preceding portion and extending along the length of the vane with one side of the U-shaped channel comprising said folded section, and a flat section contiguous with said U-shaped channel section and extending parallel to said lip, said fiat section being connected at an angle to the first section of the next succeeding vane portion, the arrangement being such that said U-shaped channels form liquid catching troughs at one end of each of said flat sections.

2. The improvement of claim 1 wherein said U- shaped channels are at the trailing ends of said flat secare held in assembled relationship between a pair of plate assemblies, the edges of which abut the inner periphery of a cylindrical housing for said vanes.

7. The improvement of claim 6 including a perforated plate spanning said housing, which plate engages the bottom edges of said vanes and supports them against gravity.

8. The improvement of claim 6 wherein each of the spacers is secured to an associated vane and is disposed in free abutment with an adjacent vane, and each of said vanes and its associated spacers is removable from said housing independently of the others. 

1. In apparatus for separating entrained liquids from a traveling stream of gas wherein the gas travels through sinuous paths formed by generally vertical vanes of zig-zag crosssectional configuration and provided with vertically extending channels which collect liquid droplets impinged upon the surfaces of the vanes as the gas travels therethrough under turbulent conditions; the improvement in said vanes characterized in that each vane is formed from a single sheet of metal, the vane having adjoining portions disposed at an angle with respect to each other to form said zig-zag configuration, each of said portions having a first section connected at an angle to the preceding portion and folded upon itself to form a folded section and a lip extending along the length of said vane, a reversely bent section contiguous with said folded section and forming a U-shaped channel spaced from the preceding portion and extending along the length of the vane with one side of the U-shaped channel comprising said folded section, and a flat section contiguous with said U-shaped channel section and extending parallel to said lip, said flat section being connected at an angle to the first section of the next succeeding vane portion, the arrangement being such that said U-shaped channels form liquid catching troughs at one end of each of said flat sections.
 2. The improvement of claim 1 wherein said U-shaped channels are at the trailing ends of said flat sections with respect to the direction of gas flow through said apparatus.
 3. The improvement of claim 1 including spacers interposed between adjacent ones of said vanes to form said sinuous paths.
 4. The improvement of claim 3 wherein said spacers are interposed between parallel flat sections of adjacent vanes.
 5. The improvement of claim 4 wherein each of said spacers is secured to an associated one of said vanes but in abutting sliding engagement with the adjacent vane.
 6. The improvement of claim 4 wherein said vanes are held in assembled relationship between a pair of plate assemblies, the edges of which abut the inner periphery of a cylindrical housing for said vanes.
 7. The improvement of claim 6 including a perforated plate spanning said housing, which plate engages the bottom edges of said vanes and supports them against gravity.
 8. The improvement of claim 6 wherein each of the spacers is secured to an associated vane and is disposed in free abutment with an adjacenT vane, and each of said vanes and its associated spacers is removable from said housing independently of the others. 